Radio frequency (rf) antenna containing element and methods of making the same

ABSTRACT

A radio frequency (RF) antenna containing element is provided. The RF antenna containing element includes a reinforced metal foil laminate antenna bonded to a carrier layer. The reinforced metal foil laminate antenna includes a metal foil layer bonded to a reinforcement layer. The reinforcement layer can mitigate tearing of the metal foil layer during formation of the antenna.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a division of U.S. application Ser. No.11/338,590 filed on Jan. 24, 2006, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present invention relates generally to communications, and moreparticularly to a radio frequency (RF) antenna containing element andmethods of making the same.

BACKGROUND

There is an increasing demand for providing products with radiofrequency (RF) circuits, such as radio frequency identification (RFID)tags and labels. RFID tags and labels can have a combination of antennasand analog and/or digital electronics, which may include, for example,communication electronics, data memory, and control logic. RFID tags andlabels are widely used to associate an object with an identificationcode. For example, RFID tags are used in conjunction with security-locksin cars, for access control to buildings, and for tracking inventory andparcels. RFID tags and labels can include active tags, which include apower source, as well as passive tags and labels, which do not.

An important element of RF circuits is the RF antenna. An RF antenna canhave a configuration where two substantial bodies of conductive materialare properly spaced from each other so as to define two antennaportions, which are bridged by a circuit chip comprising an RFtransponder. The antennas can be produced by utilizing conductive ink,or may be in the form of etched conductive foil. While products madefrom such structure function properly, the conductive ink does notprovide a high grade antenna since it cannot be as thick or asconductive, in general, as can a conductive foil. However, theconventional etching techniques for applying foil do not lend themselvesto high speed production.

SUMMARY

In one aspect of the invention, a radio frequency (RF) antennacontaining element is provided. The RF antenna containing element cancomprise a metal foil laminate antenna that includes a metal foil layerbonded to a reinforcement layer, and a carrier layer bonded to the metalfoil laminate antenna.

In another aspect of the invention, a method of forming an RF antennacontaining element is provided. The method comprises providing a metalfoil laminate bonded to a carrier layer. The metal foil laminate canhave a metal foil layer bonded to a reinforcement layer. The methodfurther comprises cutting an antenna pattern through the metal foillaminate to the carrier layer, and removing an undesired matrix portionof the reinforced metal foil laminate to provide a metal foil laminateantenna disposed on the carrier layer.

In yet another aspect of the invention, another method of forming an RFantenna containing element is provided. The method comprises providing ametal foil laminate having a metal foil layer bonded to a reinforcementlayer, patterning an antenna adhesive pattern to the reinforcementlayer, and laminating a carrier layer with the reinforcement layer. Themethod further comprises cutting an antenna pattern in registration withthe antenna adhesive pattern through the metal foil laminate to thecarrier layer, and removing an undesired matrix portion of thereinforced metal foil laminate to provide a metal foil laminate antennadisposed on the carrier layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of an RFID inlay in accordancewith an aspect of the present invention.

FIG. 2 illustrates a top view of an RFID inlay in accordance with anaspect of the present invention.

FIG. 3 illustrates a roll-to-roll process in accordance with an aspectof the present invention.

FIG. 4 illustrates another roll-to-roll process in accordance with anaspect of the present invention.

FIG. 5 illustrates a top view of an RFID inlay with antenna connectionextensions in accordance with an aspect of the present invention.

FIG. 6 illustrates a cross-sectional view of an RFID inlay with foilstrips bonded to contact ends of an antenna structure in accordance withan aspect of the present invention.

FIG. 7 illustrates a cross-sectional view of the RFID inlay of FIG. 6after undergoing a weld process in accordance with an aspect of thepresent invention.

FIG. 8 illustrates a cross-sectional view of an RFID inlay with contactextensions in accordance with an aspect of the present invention.

FIG. 9 illustrates a cross-sectional view of an RFID inlay withelectrodeposited contact extensions in accordance with an aspect of thepresent invention.

FIG. 10 illustrates a top view of cross-cut antenna structure inaccordance with an aspect of the present invention.

FIG. 11 illustrates a die cross-cut gap portion in accordance with anaspect of the present invention.

FIG. 12 illustrates a top view of the cross-cut antenna structure ofFIG. 10 after a through hole is registered within the gap of the antennastructure in accordance with an aspect of the present invention.

FIG. 13 illustrates methodology of forming an antenna containing elementin accordance with an aspect of the present invention.

FIG. 14 illustrates another methodology of forming an antenna containingelement in accordance with an aspect of the present invention.

DETAILED DESCRIPTION

The present invention relates to RF antenna containing elements andmethods of making the same. The RF antenna containing element includes areinforced metal foil laminate antenna bonded to a carrier layer. Thereinforced metal foil laminate antenna includes a metal foil layerbonded to a reinforcement layer. The reinforcement layer mitigatestearing of the metal foil layer during formation of the antenna.

Although the present examples are illustrated with respect tofabrication of an RFID inlay, the present invention is applicable to avariety of RF antenna containing elements including other intermediateassemblies for a RF antenna or final assemblies (e.g., an RFID tag).

FIG. 1 illustrates a cross-sectional view of an RFID inlay 10 inaccordance with an aspect of the present invention. The RFID inlay 10includes an antenna structure 12 supported by a carrier sheet (or layer)14. The antenna structure 12 may be releasably attached or permanentlybonded to the carrier sheet 14. The antenna structure 12 can be in theform of a variety of different shapes, sizes and types. For example, theantenna structure 12 can be a dipole antenna with opposing antennaconnection ends. The antenna structure 12 includes a gap 16 forplacement and bonding of an RFID chip (not shown) to connection ends 11and 13 of the antenna structure 12. The carrier sheet or layer 14 can bein the form of a polymeric film having a thickness in the range of about0.02 mm (1.0 mils) to about 0.08 mm (3.0 mils) (e.g., about 0.05 mm (2mils)). Examples of materials that can be used to form the carrier sheet14 include, but are not limited to, polyester films, polyethyleneterephthalate (PET) films and polyimide films.

Examples of other of materials that can be used the carrier sheet orlayer 14 include, but are not limited to, polycarbonate, polyarylate,polysulfone, a norbornene copolymer, polyphenylsulfone, polyetherimide,polyethylenenaphthalate (PEN), polyethersulfone (PES), polycarbonate(PC), a phenolic resin, polyetherester, polyetheramide, celluloseacetate, aliphatic polyurethanes, polyacrylonitrile,polylrifluoroethylenes, polyvinylidene fluorides, high densitypolyethylenes (HDPEs, poly (methyl methacrylates), a cyclic or acyclicpolyolefins. Alternatively, the carrier sheet or layer 14 can be formedof a paper material, such as a card stock paper, a bond paper or otherpaper type. The carrier sheet 14 can be formed of materials that areflexible, such that the carrier sheet 14 can be manufactured as acontinuous web, which can be wound into roll form for use in aroll-to-roll process.

The antenna structure 12 is formed from a reinforced metal foil laminate18. The reinforced metal foil laminate 18 includes a metal foil layer 20bonded to a reinforcement layer 24. The metal foil layer 20 can beformed from an aluminum foil, a copper foil, a steel foil or other metalfoil. The metal foil layer 20 can have a thickness in the range of about1.5 microns to about 20 microns (e.g., about 10 microns). Furthermore,the metal foil layer can have a tensile strength of about 100 to about140 megapascals (MPa) (e.g., about 120 Mpa) and an elongation at breakof about 20% to about 30% (e.g., 25%). The metal foil layer 20 can bebonded to the reinforcement layer 24 by an adhesive, such as atemperature and/or pressure activated adhesive. A wide variety ofadhesives may be employed to bond the metal foil layer 20 to thereinforcement layer 24. For example, a general-purpose, permanentpressure sensitive adhesive and/or laminating adhesive may be employed.By way of example, the adhesive can be an acrylic based and/orelastomeric based temperature and/or pressure activated adhesive. In oneaspect of the invention, the adhesive is an ethylene-acrylic acid (EM)copolymer adhesive, which exhibits excellent bonding characteristicsbetween metal foils and polymeric materials. The adhesive can be floodor roll coated to form an adhesive layer 22 having a thickness in therange of about 1 micron to about 3 microns (e.g., about 2 microns) witha coatweight of about 2 grams per square meter (gsm).

The reinforcement layer 24 can be in the form of a polymeric film havinga thickness in the range of about 0.002 mm (0.1 mils) to about 0.05 mm(2.0 mils) (e.g., about 0.025 mm (1 mil)). Examples of materials thatcan be used for forming a reinforcement layer include, but are notlimited to, polyester films, polyethylene terephthalate (PET) films andpolyimide films. Other polymeric materials can be employed such as thosesuggested above with respect to the carrier layer 14. Alternatively, thereinforcement layer 24 can be formed of a paper material. Thereinforcement layer 24 can be formed of materials that are flexible,such that the reinforcement layer 24 in combination with the adhesivelayer 22 and metal layer 20 can be manufactured as a continuous web,which can be wound into roll form for use in a roll-to-roll process.

In one aspect of the invention, the antenna structure 12 is formed onthe carrier sheet 14 by performing a partial die cut with a die (notshown) having a shape generally matching a shape of the desired antennastructure. The die cuts through the reinforced metal foil laminate 18and an adhesive layer 26 to the underlying carrier layer 14. In thisaspect of the invention, the carrier layer 14 can have a releasecoating, such that the undesired portions or waste material (hereinafterreferred to as the “matrix material” or “matrix portion”) of thereinforced metal foil laminate 18 and underlying adhesive material 26are readily removed, such that only the reinforced metal foil laminateportion of the desired antenna structure 12 remains on the carrier layer14. The adhesive layer 26 can be a rubber based pressure activatedadhesive. The adhesive can be flood or roll coated to form the adhesivelayer 26 having a thickness in the range of about 5 micron to about 25microns (e.g., about 15 microns) with a coatweight of about 25 gsm.

In another aspect of the invention, the antenna structure 12 is formedon the carrier layer 14 by applying a patterned adhesive 26 having ashape generally matching a shape of the desired antenna structure 12 ona back side of the reinforcement layer 24 of the reinforced metal foillaminate 18. The carrier layer 14 can be laminated with thereinforcement layer 24, and the patterned adhesive 26 can then be cured.In one aspect of the invention, the patterned adhesive 26 is anultra-violet (UV) curable adhesive. A partial die cut with a die havinga shape generally matching a shape of the desired antenna structure 14is performed. The die cuts through the reinforced metal foil laminate 18to the underlying carrier layer 14 in registry with the patternedadhesive 26 to form the antenna structure 12. The undesired portions or“matrix material” of the reinforced metal foil laminate 18 and undesiredadhesive material are readily removed, such that only the reinforcedmetal foil laminate portion of the desired antenna structure 12 remainson the carrier layer 14. The remaining adhesive layer 26 of the antennastructure 12 can have a thickness in the range of about 5 micron toabout 25 microns (e.g., 15 microns) with a coatweight of about 25 gsm.

FIG. 2 illustrates a top view of an RFID inlay 30 in accordance with anaspect of the present invention. The RFID inlay 30 includes a carrierlayer 32 and an antenna structure 34 formed of a reinforced metal foillaminate 35. The antenna structure 34 includes a generally T-shapedopening 36 that defines antenna contact ends 40 and 42, which are spacedapart via a gap 38. It is to be appreciated that the present inventionis applicable to a variety of antenna types, shapes and sizes. The gap38 is sized to allow placement of an RFID chip (not shown) that can bebonded to the carrier layer 32 with bonding pads or contacts of the RFIDchip coupled to respective antenna contact ends 40 and 42 via contactextensions (not shown). The antenna structure 34 can be formed employinga partial die cut in the shape of the antenna structure 34 on areinforced metal foil laminate 35 bonded to the carrier layer 32 withthe remaining matrix material of the reinforced metal foil laminatebeing removed. The materials and dimensions of the reinforced metal foillaminate, adhesives and carrier layer 32 can be selected to be formed ofmaterials that are durable and flexible, such that the carrier sheet 32,adhesives and reinforced metal foil laminate 35 can be manufactured as acontinuous web which can be wound into roll form for use in aroll-to-roll process.

It is to be appreciated that the die employed in the partial die cut mayhave certain feature size limitations, such that the gap 38 formedbetween the antenna connection ends 40 and 42 is too large to directlyconnect the RFID chip. Therefore, contact extensions can be provided tocouple the contact pads of the chip to the antenna connection ends 40and 42. A number of methodologies can be employed to form contactextensions, such as the use of straps, interposers and carriers as isknown in the art.

FIG. 3 illustrates a roll-to-roll process 50 for forming an antennastructure in accordance with an aspect of the present invention. In theroll-to-roll process, a web 51 comprising a reinforced metal foillaminate bonded to a carrier layer via an adhesive layer is unwound viaan unwinder 52 and fed to a die cutter 54. The reinforced metal foillaminate includes a metal foil layer bonded to a reinforcement layer viaan adhesive layer as discussed above with respect to FIGS. 1-2. Thereinforcement layer provides the metal foil layer with additionalsupport to mitigate tearing or ripping of the metal foil during theremoval of the undesired matrix portion of the web 51. The die cutter 54repeatedly performs a partial die cut with a die having a shapegenerally matching a shape of the desired antenna structure as the web51 passes through the die cutter 54. The die cutter 54 can be amechanical die cutter, such as a rotary die anvil. It is to beappreciated that although the antenna pattern described herein is formedvia a die cutter, other methodologies of performing a die cut throughthe reinforced metal foil laminate to the carrier layer may be employed,such as laser die cutting, microperforation, and other cuttingtechniques.

The die of the die cutter 54 cuts through the reinforced metal foillaminate and an adhesive layer to the underlying carrier layer toprovide a cut that defined the desired antenna structure and theundesired matrix portion of the reinforced metal foil laminate. The web51 is then passed through a stripper 60 that strips and separates theundesired matrix portion of the reinforced metal foil laminate from thedesired reinforced metal foil laminate antenna structures and thesupporting carrier layer. The reinforced metal foil laminate antennastructure and carrier layer form a web 61 that is wound into anantenna/carrier roll via a first rewinder 58. The matrix portion of thereinforced metal foil laminate form another web 63 that is wound into amatrix roll via a second rewinder 56. It has been determined that theabove process can produce antenna structures at a rate of about 250 feetper minute.

FIG. 4 illustrates a roll-to-roll process 80 for forming an antennastructure in accordance with another aspect of the present invention. Areinforced metal foil laminate in the form of web 81 is unwound via anunwinder 82 and fed to an adhesive pattern coater 86. The adhesivepattern coater 86 can be any conventional pattern coating equipmentemployed for that purpose. The reinforced metal foil laminate includes ametal foil layer bonded to a reinforcement layer via an adhesive layeras discussed above with respect to FIGS. 1-2. The adhesive patterncoater 86 repeatedly applies an adhesive pattern substantially in theshape of the desired antenna pattern to a back of the reinforcementlayer of the web 81 as it passes through the adhesive pattern coater 86.The adhesive employed on the adhesive pattern is, for example, a UVcurable adhesive.

The web 81 is then fed through a set of laminating rollers 88 along witha carrier web 85. The carrier web 85 is unwound via an unwinder 84 andfed to the set of laminating rollers 88, such that the web 81 and thecarrier web 85 are sandwiched together and laminated. Alternatively, asillustrated with dashed lines, the carrier web 85 can be fed to anadhesive pattern coater 87 to repeatedly apply an adhesive patternsubstantially in the shape of the desired antenna pattern to a front ofthe carrier web 85 as it passes through the adhesive pattern coater 87.A resultant web 91 includes the reinforced metal foil laminate andcarrier web with adhesive antenna patterns formed therebetween.

The resultant web 91 passes through a UV station 90 that provides UVlight through the carrier layer of the resultant web 91 to cure theadhesive antenna patterns. The carrier layer is selected to be aUV-transparent layer that can be formed from a UV-transparent material,such as a UV-transparent polymeric material. The resultant web 91 isthen fed to a die cutter 92. The die cutter 92 repeatedly performs apartial die cut with a die having a shape generally matching a shape ofthe desired antenna structure, as the resultant web 91 passes throughthe die cutter 92. The partial die cut is in registration with theantenna adhesive patterns, such that the partial die cut issubstantially aligned with the adhesive antenna pattern. The die cutter92 can be a variety of different mechanical die cutters, such as arotary die anvil. The die cuts through the reinforced metal foillaminate and the adhesive of the adhesive antenna pattern of theresultant web 91 to the underlying carrier layer to provide a cutgenerally at or within the outside perimeter of the adhesive antennapattern. The resultant web 91 is separated, such that the reinforcedmetal foil laminate antenna structure and carrier layer form a web 97.The web 97 is then wound into an antenna/carrier roll via a firstrewinder 96. The undesired matrix portion of the reinforced metal foillaminate and excess adhesive form another web 95 that is wound into amatrix roll via a second rewinder 94. It is been determined that theabove process can produce antenna structures at a rate of at least about50 feet per minute.

As previously stated, the die employed in the partial die cut may havecertain feature size limitations, such that the gap formed between theantenna connection ends is too large to directly connect the RFID chip.Straps and/or interposers can be attached to the chip prior to placementon an RFID inlay, but at significant costs to the inlay and the finalRFID tag. In accordance with an aspect of the present invention,extensions may be employed to provide electrical coupling between theRFID chip and the antenna. These extensions can be fabricated at a lowcost in a manner that allows for direct chip placement.

Additionally, if the metal foil layer employed to form the antennastructure is aluminum foil or copper foil, an oxide layer that readilyforms on the aluminum foil or copper foil can create additionalresistances in bonding the RFID chip to the antenna. Therefore, portionsof the oxide layer on the antenna for which contact is to be made canreadily be removed. Removal of portions of the oxide layer can beaccomplished by a variety of techniques. For example, removal can beaccomplished by scratching, applying pressure, and/or puncturing contactareas or contact ends on the antenna. Alternatively y, conductive bumpscan provided at the contact areas or contact ends. The conductive bumpscan include a multitude of small, hard particles (e.g., diamondparticles) with a multitude of sharp paints for penetrating the oxidelayer at the contact area. Additionally, copper contacts can beelectroplated to the contact area of the antenna to penetrate the oxidelayer.

FIGS. 5-8 illustrate the formation of extensions on an antenna structureto allow for direct RFID chip placement. In the illustrated examples,the oxide layer over the antenna contact area has been removed or can beremoved during formation of the extensions by any of the techniquesdiscussed above.

FIG. 5 illustrates a top view of an RFID inlay 100 with antennaconnection extensions in accordance with an aspect of the presentinvention. The RFID inlay 100 includes a carrier layer 102 and anantenna structure 104 formed of a reinforced metal foil laminate 105.The antenna structure 34 includes a generally T-shaped opening 106 thatdefines antenna contact ends 110 and 112 spaced apart via a gap 108. Thegap 108 is sized to allow placement of an RFID chip 118 (shown withdashed lines) with bonding pads or contacts coupled to respectiveantenna contact ends 110 and 112 via contact extensions 114 and 116,respectively.

In one aspect of the invention, the contact extensions 114 and 116 canbe formed by transferring foil (e.g., copper foil) in the requisitepattern onto the surface of the contact ends 110 and 112 of the antennaand/or the carrier layer to either enhance the foil of the antenna forbonding or to build an adjoining feature for chip bonding. Thetransferred foil can be welded to the metal foil using, for example,electrical or magnetic induction welding or impact/explosive welding orultrasonic welding. The weld head can be selected to provide the desiredshape of the contact extensions 114 and 116. Alternatively, thetransferred foil can be bonded to the contact ends 110 and 112 via anadhesive, or temporarily bonded via an adhesive prior to welding. Thetransferred foil can be in the form of a web that can be transferred(e.g., heat transferred) from a substrate via a release layer in aroll-to-roll process.

In another aspect of the invention, the contact extensions 114 and 116can be formed by printing conductive inks and/or adhesives of theappropriate thicknesses in the extension feature areas, for example,from the carrier layer to the contact ends 110 and 112. Alternatively,chip bond pads can be formed on the carrier layer employing conductiveinks and/or adhesives with a transferred foil contact extensionproviding electrical conductivity between the chip bond pads and theantenna contact ends 110 and 112.

In yet another aspect of the invention, the contact extensions 114 and116 can be formed by electroplating or electro-deposition of copper ontothe contact ends 110 and 112 of the antenna structure, such that thecopper extends over the gap providing chip bond pads for direct chipplacement. Alternatively, chip bond pads can be formed on the carrierlayer employing conductive inks and/or adhesives with an electroplatedcopper contact extension providing electrical conductivity between thechip bond pads and the antenna contact ends 110 and 112.

FIG. 6 illustrates a cross-sectional view of an RFID inlay 130 inaccordance with an aspect of the present invention. The RFID inlay 130includes an antenna structure 132 supported by a carrier sheet (orlayer) 134. The antenna structure 132 includes a gap 136 for placementand bonding of an RFID chip to contact ends 147 and 149 of the antennastructure 132. The antenna structure 132 is formed from a reinforcedmetal foil laminate 138. The reinforced metal foil laminate 138 includesa metal foil layer 140 bonded to a reinforcement layer 144 via anadhesive layer 142. The metal foil layer 140 can be formed, for example,from an aluminum foil, a copper foil, steel foil or other metal foil.The reinforced metal foil laminate 138 is bonded to the carrier layer134 via an adhesive layer 146.

A first foil strip 148 is bonded to a first contact end 147 of theantenna structure 132 with a portion of the first foil strip extendingover the gap 136, and a second foil strip 150 is bonded to a secondcontact end 149 with a portion of the second foil strip extending overthe gap 136. The first and second foil strips 148 and 150 can be formedof, for example, copper. The first and second foil strips 148 and 150can have a thickness in the range of about 1 micron to about 3 microns(e.g., 2 microns). The first and second foil strips 148 and 150 canreside on a web and can be transferred from a substrate via a releaselayer and/or a heat transfer in a roll-to-roll process.

The first and second foil strips 148 and 150 can be bonded to the firstand second contact ends 147 and 149, respectively via an adhesive. Theoxide layer over the first and second contact ends 147 and 149 can beremoved by scratching, applying pressure and/or puncturing contact areason the first and second contact ends 147 and 149 on the antennastructure 132. Alternatively, the first and second foil strips 148 and150 can be bonded to the first and second contact ends 147 and 149 bywelding (e.g., a spot weld), thus concurrently bonding the foil strips148 and 150 and penetrating the oxide layer over the first and secondcontact ends 147 and 149. Furthermore, contact pads can be formed overthe first and second contact ends 147 and 149 by employing conductivebumps with a multitude of hard particles, or electroplating copper toform contact pads prior to placement and bonding of the foil strips 148and 150.

FIG. 7 illustrates a cross-sectional view of the RFID inlay 130 of FIG.6 after undergoing a weld process in accordance with an aspect of thepresent invention. The weld process includes employing a weld headhaving a shape that forms contact extensions 152 and 156 into a desiredpattern that allows for direct chip placement. The weld head canconcurrently shape the first and second foil strips 148 and 150 intocontact extensions and weld the contact extensions 152 and 156 to thefirst and second contact ends 147 and 149 of the antenna 132 (i.e.,metal-to-metal weld) and to the carrier layer 134 (i.e.,metal-to-plastic weld). As illustrated in FIG. 7, the contact extensions152 and 156 have generally right angle bends at contact ends 147 and 149of a top surface of the antenna 132 and generally right angle bends at atop surface of the carrier layer 134. A first end of each respectivecontact extension 152 and 156 (foil strip) is electrically coupled to arespective contact area of the antenna 132 with a second end of eachrespective contact extension 152 and 156 (foil strip) provide bondingpads for direct placement of an RFID chip 158 illustrated with dashedlines.

It is to be appreciated that the contact extensions 152 and 156 can bebonded with adhesive and the weld head being replaced with a print heador shaping tool for forming the shape of the contact extensions 152 and156. Additionally, the first and second foil strips 148 and 150 can bereplaced with a single foil strip that is cut and removed during orafter the shaping process.

FIG. 8 illustrates a cross-sectional view of an RFID inlay 170 inaccordance with an aspect of the present invention. The RFID inlay 170includes an antenna structure 172 supported by a carrier sheet (orlayer) 174. The antenna structure 172 includes a gap 176 for placementand bonding of an RFID chip to connection ends of the antenna structure172. The antenna structure 172 is formed from a reinforced metal foillaminate 178. The reinforced metal foil laminate 178 includes a metalfoil layer 180 bonded to a reinforcement layer 184 via an adhesive layer182. The metal foil layer 180 can be formed, for example, from analuminum foil, a copper foil, a steel foil or other metal foil. Thereinforced metal foil laminate 178 is bonded to the carrier layer 174via an adhesive layer 186.

A first contact extension 188 and a second contact extension 190 extendfrom antenna contact ends 187 and 189 of the antenna 172 into the gap176. The contact extensions 188 and 190 can be formed by building upconductive ink and/or conductive adhesive layers from the carrier layer174 to the contact ends 187 and 189 of the antenna 172. Alternatively,conductive ink and/or conductive adhesive can be built up on the carrierlayer 174 with contact pads on the contact ends 187 and 189 of theantenna 172 being formed by employing additional layers of conductiveink and/or adhesive extending from the contact ends 187 and 189 of theantenna 172 into the gap 176. Furthermore, copper extensions can beelectroplated from the contact ends 187 and 189 of the antenna 172 tothe conductive ink and/or adhesive residing in the gap 176. An RFID chip192 illustrated with dashed lines can be directly placed on a surface ofthe first and second contact extensions 188 and 190. Furthermore, thecontact extensions 188 and 190 can be formed by providing bond pads thatextend from the contact extensions 188 and 190 via conductive ink orconductive adhesive on the carrier layer 174 in the gap 176, such thatthe RFID chip 192 can be directly placed on the bond pads on the carrierlayer 174 in the gap 176.

FIG. 9 illustrates a cross-sectional view of an RFID inlay 200 inaccordance with an aspect of the present invention. The RFID inlay 200includes an antenna structure 202 supported by a carrier sheet (orlayer) 204. The antenna structure 202 includes a gap 206 for placementand bonding of an RFID chip to antenna connection ends 217 and 219 ofthe antenna structure 202. The antenna structure 202 is formed from areinforced metal foil laminate 208. The reinforced metal foil laminate208 includes a metal foil layer 210 bonded to a reinforcement layer 214via an adhesive layer 212. The metal foil layer 210 can be formed froman aluminum foil, a copper foil, steel foil or other metal foil. Thereinforced metal foil laminate 208 is bonded to the carrier layer 204via an adhesive layer 216.

A first contact extension 218 and a second contact extension 220 extendfrom respective contact ends 217 and 219, respectively, of the antenna202 into the gap 206 via an electroplating or electro-depositionprocess. As illustrated in FIG. 9, a voltage potential (V+) is appliedto antenna contact ends across the gap 206 immersed in an electrolyticmedium. The voltage potential causes electro-deposition of contacts onthe tips of the contact ends 217 and 219 of the antenna 202 into the gap206. In the example of FIG. 9, the electrolytic medium is copper sulfate(CuSo,) resulting in the electro-deposition of copper on the metal foillayer 210 to form the first contact extension 218. The polarity of thevoltage potential at the antenna contact ends 217 and 219 to form thesecond contact extension 220. The first and second contact extensions218 and 220 form bonding pads for direct placement of an RFID chip 222illustrated in dashed lines.

FIG. 10 illustrates a top view of a cross-cut antenna structure 230 inaccordance with an aspect of the present invention. The cross-cutantenna structure 230 is formed from a reinforced metal foil laminate.The cross-cut antenna structure 230 provides for direct RFID chipplacement without the need for contact extension. The cross-cut antennastructure 230 includes a generally T-shaped opening 232 that formsantenna contact ends 234 and 236 spaced apart via a gap 235. TheT-shaped opening 232 is formed from a die cut that employs a die havinga generally T-shape with a generally X-shaped gap portion.

FIG. 11 illustrates a die cross-cut gap portion 250. The generallyX-shaped gap portion of the die separates the reinforced metal foillaminate into four distinct quadrants 1, 2, 3, and 4. The undesiredmatrix portion of the reinforced metal foil laminate can be removed inquadrants 2 and 4 leaving the reinforced metal foil laminate in quadrant1 and 3 with opposing generally pointed contact end tips separated bythe width (e.g., about 6 microns to about 8 microns) of the die cut. Thedie can be selected to provide a desired width between the tips ofopposing contact ends 234 and 236.

Referring again to FIG. 10, bond pads 238 and 240 can be provided oncontact ends 234 and 236, respectively. The bond pads 238 and 240 can beformed from an electrolytic process to form copper contact bond pads. ANRFID chip 242 as illustrated with dashed lines can be placed directlyacross the tips of the opposing contact ends 234 and 236. However, themetal foil under the RFID chip can lead to problems associated withelectrical interaction with the chip functions, for example due tocapacitance associated with the metal foil. Therefore, an RFID chip 244can be rotated as illustrated with dashed lines and placed across thetips of the opposing contact ends 234 and 236 at an offset to mitigatethe amount of metal foil under the RFID chip 244. Furthermore, anothermethodology to mitigate the amount of metal foil under the chip is toregister a through hole 246 within the gap 235 as illustrated in FIG.12. The through hole 246 can be formed by punching through and removinga predetermined amount of materials of the tips of opposing contact ends234 and 236 to define a predetermined width across the gap 235. An RFIDchip 248 as illustrated with dashed lines can be directly placed acrossthe opposing contact ends 234 and 236.

In view of the foregoing structural and functional features describedabove, methodologies will be better appreciated with reference to FIGS.13-14. It is to be understood and appreciated that the illustratedactions, in other embodiments, may occur in different orders and/orconcurrently with other actions. Moreover, not all illustrated featuresmay be required to implement a method.

FIG. 13 illustrates a methodology of forming an antenna containingelement in accordance with an aspect of the present invention. Themethodology begins at 300 where a reinforced metal foil laminatedisposed on a carrier layer is provided. The reinforced metal foillaminate can be formed from a metal foil layer bonded to a reinforcementlayer via an adhesive layer. The reinforced metal foil laminate can bebonded to the carrier via an adhesive layer. At 310, an antenna patternis die cut through the reinforced metal foil laminate to the carrierlayer. At 320, the undesired matrix portion of the reinforced metal foillaminate is removed, such that an antenna structure in the shape of theantenna pattern remains on the carrier layer.

FIG. 14 illustrates another methodology of forming an antenna containingelement in accordance with an aspect of the present invention. Themethodology begins at 400 where an adhesive antenna pattern is printedon one of a reinforcement layer side of a reinforced metal foil laminateand a carrier layer. The reinforced metal foil laminate can be formedfrom a metal foil layer bonded to a reinforcement layer via an adhesivelayer. At 410, the carrier layer is laminated to the reinforcement layerside of a reinforced metal foil laminate. At 420, an antenna pattern isdie cut through the reinforced metal foil laminate to the carrier layerin registration with the adhesive antenna pattern. At 430, the undesiredmatrix portion of the reinforced metal foil laminate is removed, suchthat an antenna structure in the shape of the antenna pattern remains onthe carrier layer.

What have been described above are examples of the present invention. Itis, of course, not possible to describe every conceivable combination ofcomponents or methodologies for purposes of describing the presentinvention, but one of ordinary skill in the art will recognize that manyfurther combinations and permutations of the present invention arepossible. Accordingly, the present invention is intended to embrace allsuch alterations, modifications and variations that fall within thespirit and scope of the appended claims.

1. A method of forming a radio frequency (RF) antenna containingelement, the method comprising: providing a reinforced metal foillaminate comprising a metal foil layer bonded to a reinforcement layer,and a carrier layer bonded to the metal foil laminate; cutting anantenna pattern through the metal foil laminate to the carrier layer;and removing an undesired matrix portion of the reinforced metal foillaminate to provide a metal foil laminate antenna disposed on thecarrier layer.
 2. The method of claim 1, wherein the cutting an antennapattern through the metal foil laminate to the carrier layer comprisesperforming a partial die cut with a die cutter.
 3. The method of claim2, wherein the performing a partial die cut comprises performing across-cut with a die having a generally X-shaped gap portion thatseparates a gap area into four distinct quadrants, wherein the removingan undesired matrix portion of the reinforced metal foil laminatecomprises removing two of the four distinct quadrants to provideopposing generally painted antenna contact end tips.
 4. The method ofclaim 3, further comprising registering a through hole within the gaparea to remove portions of the antenna contact end tips to define a gapof a desired width between the antenna contact end tips.
 5. The methodof claim 1, wherein the metal foil laminate bonded to a carrier layer isunwound from a web and fed to a die cutter for repeatedly die cuttingantenna patterns through the metal foil laminate to the carrier layer toform a plurality of reinforced metal foil laminate antenna structures,the web being stripped by a stripper that separates the undesired matrixportion from the plurality of reinforced metal foil laminate antennastructures, the plurality of reinforced metal foil laminate antennastructures being wound into an antenna/carrier roll via a first rewinderand the undesired matrix portion being wound into a matrix roll via asecond rewinder.
 6. The method of claim 1, wherein the metal foil layeris formed from aluminum foil that has a thickness in the range of about1.5 microns to about 20 microns, the reinforcement layer is formed froma polymeric film having a thickness in the range of about 1 mils toabout 1 mil, and an adhesive layer that bonds the metal foil layer tothe reinforcement layer has a thickness in the range of about 1 micronto about 3 microns.
 7. The method of claim 1, wherein the cutting anantenna pattern through the metal foil laminate to the carrier layerfurther comprises cutting the antenna pattern through an adhesive layerthat bonds the reinforced metal foil laminate to the carrier layer, thecarrier layer including a release layer to facilitate removing of theundesired matrix portion.
 8. The method of claim 1, further comprisingforming contact extensions that extend between antenna contact ends intoa gap between the antenna contact ends to allow for direct RFID chipplacement.
 9. The method of claim 8, wherein the forming contactextensions comprises: bonding a first foil strip to a first antennacontact end, such that the first copper foil strip overlies a portion ofthe gap; bonding a second foil strip to a second antenna contact end,such that the second copper foil strip overlies a portion of the gap;concurrently shaping the first foil strip to have a generally rightangle bend at the first antenna contact end and a generally right anglebend at a top surface of the carrier layer, and the second foil strip tohave a generally right angle bend at the second antenna contact end anda generally right angle bend at the top surface of the carrier layer,such that ends of the first and second foil strips at the top surface ofthe carrier layer provide bonding pads for direct chip placement. 10.The method of claim 9, wherein the concurrently shaping the first foilstrip and the second foil strip further comprises welding the first foilstrip to the first antenna contact end and the top surface of thecarrier layer and the second foil strip to the second antenna contactend and the top surface of the carrier layer with a weld head having adesired shape for shaping the first and second foil strips into firstand second contact extensions.
 11. The method of claim 8, wherein theforming contact extensions comprises electroplating copper contactextensions via an electroplating process.
 12. The method of claim 8,wherein the forming contact extensions comprises building layers of atleast one of copper, conductive ink and conductive adhesive from thecarrier layer to the respective antenna contact ends.
 13. A method offorming a radio frequency (RF) antenna containing element, the methodcomprising: providing a metal foil laminate having a metal foil layerbonded to a reinforcement layer; providing a carrier layer; patterningan antenna adhesive pattern to one of the reinforcement layer andcarrier layer; laminating the carrier layer and the reinforcement layer;cutting an antenna pattern in registration with the antenna adhesivepattern through the metal foil laminate to the carrier layer; andremoving an undesired matrix portion of the reinforced metal foillaminate to provide a metal foil laminate antenna disposed on thecarrier layer.
 14. The method of claim 13, wherein antenna adhesivepattern is formed from a ultra-violet (UV) curable adhesive, the antennaadhesive pattern being exposed to a UV light source prior to the cuttingan antenna pattern.
 15. The method of claim 13, wherein the cutting anantenna pattern through the metal foil laminate to the carrier layercomprises performing a partial die cut with a die cutter.
 16. The methodof claim 15, wherein the performing a partial die cut comprisesperforming a cross-cut with a die having a generally X-shaped gapportion that separates a gap area into four distinct quadrants, whereinthe removing an undesired matrix portion of the reinforced metal foillaminate comprises removing two of the four distinct quadrants toprovide opposing generally painted antenna contact end tips.
 17. Themethod of claim 16, further comprising registering a through hole withinthe gap area to remove portions of the antenna contact end tips todefine a gap of a desired width between the antenna contact end tips.18. The method of claim 13, wherein the metal foil laminate is unwoundfrom a first web and a carrier layer is unwound from a second web, oneof the first web and second web being fed to an adhesive pattern coaterfor patterning an antenna adhesive pattern to one of the reinforcementlayer and the carrier layer and laminated the carrier layer and thereinforcement layer to provide a resultant web, the resultant web is fedto a die cutter for repeatedly die cutting antenna patterns inregistration with the adhesive antenna patterns through the metal foillaminate to the carrier layer to form a plurality of reinforced metalfoil laminate antenna structures, the resultant web being stripped toseparate an undesired matrix portion from the plurality of reinforcedmetal foil laminate antenna structures, the plurality of reinforcedmetal foil laminate antenna structures being wound into anantenna/carrier roll via a first rewinder and the undesired matrixportion being wound into a matrix roll via a second rewinder.
 19. Themethod of claim 13, wherein the metal foil layer is formed from one ofaluminum foil that has a thickness in the range of about 1.5 microns toabout 20 microns, the reinforcement layer is formed from one of apolymeric film and paper, the reinforcement layer having a thickness inthe range of about 0.1 mils to about 1 mil, and an adhesive layer thatbonds the metal foil layer to the reinforcement layer, the adhesivelayer has a thickness in the range of about 1 micron to about 3 microns.20. The method of claim 13, further comprising forming contactextensions that extend between antenna contact ends into a gap betweenthe antenna contact ends to allow for direct chip placement.
 21. Themethod of claim 20, wherein the forming contact extensions comprises:bonding a first foil strip to a first antenna contact end, such that thefirst copper foil strip overlies a portion of the gap; bonding a secondfoil strip to a second antenna contact end, such that the second copperfoil strip overlies a portion of the gap; concurrently shaping the firstfoil strip to have a generally right angle bend at the first antennacontact end and a generally right angle bend at a top surface of thecarrier layer, and the second foil strip to have a generally right anglebend at the second antenna contact end and a generally right angle bendat the top surface of the carrier layer, such that ends of the first andsecond foil strips at the top surface of the carrier layer providebonding pads for direct chip placement.
 22. The method of claim 21,wherein the concurrently shaping the first foil strip and the secondfoil strip further comprises welding the first foil strip to the firstantenna contact end and the top surface of the carrier layer and thesecond foil strip to the second antenna contact end and the top surfaceof the carrier layer with a weld head having a desired shape for shapingthe first and second foil strips into first and second contactextensions.
 23. The method of claim 20, wherein the forming contactextensions comprises electroplating copper contact extensions via anelectroplating process.
 24. The method of claim 20, wherein the formingcontact extensions comprises building layers of at least one of copper,conductive ink and conductive adhesive from the carrier layer to therespective antenna contact ends.